1. Field of the Invention
The present invention relates to an arrangement for manufacturing non-palletized packaging units which are completely surrounded with shrinking foil. The packaging units are formed by several layers of objects which are stacked on top of each other.
2. Description of the Prior Art
In a method for manufacturing the packaging units described above, initially several layers of objects having the same surface area are stacked one on top of the other and then a special layer of objects is stacked on top of the other layers in such a way that at least two parallel recesses are formed into which support members of a lifting device later engage. A first layer of shrinking foil is then placed on the entire stack. Subsequently, the shrinking foil is shrunk onto the stack by the application of heat. The entire stack is then turned by 180.degree., so that the special layer with the recesses is placed at the bottom. A second layer of shrinking foil is then placed on the stack and shrunk onto the stack by the application of heat. The shrinking foil in the region of the recesses is formed to conform with the shape of the recesses prior to turning the stack and/or after shrinking the second layer of shrinking foil onto the stack.
An apparatus for carrying out the method described above includes a shrinking foil application device, a shrinking device, a turning device having two conveyor surfaces which can be moved against the stack from two opposite sides, and a single shaping device which is combined with the turning device. The shaping device serves to conform the shrinking foil to the shape of the recesses. The shaping device includes shaping tools which cooperate with one of the two conveyor surfaces of the turning device. The shaping tools can be moved into a shaping position prior to the turning of the stack and can be maintained in the shaping position during the turning of the stack.
In a known arrangement of this type, for example, from German Patent No. 27 43 568, the shaping tools in the turning device are formed by a two-piece, relatively complicated shaping frame. Before a stack is moved into the turning device, the shaping frame, together with a first shrinking foil attached to the shaping frame, is moved toward one of the two conveyor surfaces of the turning device. After the stack has been moved into the turning device, the shaping frame and the first shrinking foil are moved from the top into the recesses formed by the special layer of the stack as the two conveyor surfaces of the turning device are moved toward each other. After the stack has been turned, the shaping frame is moved out of the turning device together with the turned stack and is transported together with the stack to a second shrinking foil application device and a second shrinking device. Subsequently, the shaping frame is separated from the stack and returned into the turning device. This known arrangement is very useful for forming stacks which are stable and retain their shape. However, the arrangement is very complicated in its construction and requires a substantial amount of space.
In arrangements of the above-described type requiring a small output, it is known from German Patent No. 27 60 249 to reduce the structural requirements by mounting the turning device between a single shrinking foil application device and a single shrinking device. In this arrangement, the stack of objects merely is passed through the turning device without turning the stack after the first shrinking foil has been applied to the stack. Subsequently, the first shrinking foil is shrunk onto the stack in the shrinking device. The stack is then returned to the turning device, is turned in the turning device and is moved back to the shrinking foil application device, where the second shrinking foil is slid over the stack and, after again merely passing through the turning device, is transported into the shrinking device for shrinking on the second shrinking foil. However, for shaping the foil in the recesses, this known arrangement requires two additional shaping devices, i.e., a shaping device arranged in front of the shrinking device for shaping the shrinking foil in the recesses when the recesses are located at the top and another shaping device located after the shrinking device for shaping the shrinking foil in the recesses when these recesses are at the bottom after the stack has been turned.
It is, therefore, the primary object of the present invention to provide an apparatus for manufacturing non-pelletized packaging units surrounded completely with shrinking foil in which the space required for the arrangement is small and the structural requirements are reduced. This object is to be met particularly in an arrangement requiring relatively small output, similar to the arrangement disclosed in German Patent No. 27 60 249. Also, the packaging unit to be formed with the arrangement according to the invention is to be stable and is to retain its shape as much as possible, similar to the arrangement according to German Patent No. 27 43 568.